Adelaide Geosyncline

The Adelaide Geosyncline is a geological term referring to a large, linear depression in the Earth's crust where significant sediment accumulation occurred. This process, known as subsidence, led to the deposition of thousands of feet of sediment. As deposition continued, the accumulated sediments experienced folding, crumpling, and faulting. The geosyncline's history typically concluded with the intrusion of igneous rocks and regional uplift, transforming the trough into a belt of folded mountains.1

Within the Adelaide Geosyncline, two distinct segments are recognized in the rock strata: the eugeosyncline and the miogeosyncline. The eugeosyncline, the outer, deepwater segment, is characterized by thick volcanic sequences and sediments like graywackes and cherts, indicating deepwater deposition. The miogeosyncline, the inner segment, contains rocks such as limestones and well-sorted quartzose sandstones, suggesting shallow-water formation. The Sturtian Series, a division of Proterozoic rocks in South Australia, is a significant part of the Adelaide Geosyncline, with glacial deposits found within its sequence.12